Projected goals of this work include: (a) to demonstrate MTV-associated antigen-antibody complexes in the kidney of C3H/He mice; (b) to determine the physical and chemical characteristics of tumor antigens; (c) to test these components to determine their antigenic properties; (d) to analyze which of the purified fractions elicits the production of protective antibody when used for immunization; and (e) to develop new and/or adapt known biochemical methods for the isolation and characterization of viruses and/or tumor-associated antigens.